The Master Server if separate from the Media Server does not have a huge impact on backup performance *unless* there are lots of files for a Windows client. The unless is because at intervals the client sends the Master the list of files backed up - I think at each checkpoint. The backup does not resume until the client gets the 'ACK' from the Master as I understand it. If the file list (being sent for the catalog) is huge there may be enough of a pause to cause the backup to appear to stop. If the backup is going direct to tape that is bad news as the tape may stop and back-hitch. Often. If staging to disk is does not matter.
Otherwise I'd recommend first making sure the tape buffer size is good, 256KB for LTO still seems as good as it gets. Then set the NET_BUFFER_SZ to the same. Long ago it used to be said that it should be +1K but I don't think that is advised any more, so 262144 is a good NET_BUFFER_SZ. Just use that everywhere and it seems to work OK. As someone noted, some Windows drivers will not let you set a 256KB tape block size without first doing some driver configuration. Maximum_SG_List is I think the registry setting but it is driver specific and newer (StorPort) drivers should not need it. So only bother if it fails if you set the buffer size to 256KB. NB any restore server must also be able to read the block size that you write. I have in the past found on the LAN side that although you set NET_BUFFER_SZ and there is no error, if you turn tracing on I think bptm or bpbkar above 4 you may see it ask for what you set and be given less by the OS. That does get OS specific and I don't think it happens with Windows. Definitely seen it with Solaris, and the fix is to adjust the ndd tcp settings. The tuning is done by looking at the wait & delay counts and adjusting as best you can. Don't overlook on the client defragmenting the disks. Windows defaults are much better from 2003 onwards. You can set TCP window options but I am not convinced it has great effect in a typical LAN, might on a WAN backup. Jumbo Frames does make a big difference but it takes a lot of negotiation with network teams and some application owners may get nervous unless you are on a dedicated backup NIC. Older NICs & switches may not support it or may have bizarrely different maximum values anywhere from 8192 to 9194 bytes, and you need to set an exact same value everywhere. Regards William From: veritas-bu-boun...@mailman.eng.auburn.edu [mailto:veritas-bu-boun...@mailman.eng.auburn.edu] On Behalf Of Simon Weaver Sent: 28 November 2012 13:08 To: veritas-bu@mailman.eng.auburn.edu Subject: [Veritas-bu] Tuning Settings on NetBackup Client (Windows) All, Following on from the documentation below, can I just ask, that if I want to improve performance on a Windows 2003 client, where the backup is done on the LAN, if I follow this document, am I right in thinking, these settings should be put in place on the MASTER Server as well? http://www.symantec.com/business/support/index?page=content&id=TECH19206 I ask, because the document talks about a Media Server, which a Master Server could well be, and in this environment, I have one master that does ALL the backups. Reason I am looking at this, is to try and improve backup performance for the LAN, but it is a Windows client. Thanks, Simon ________________________________ This e-mail was sent by GlaxoSmithKline Services Unlimited (registered in England and Wales No. 1047315), which is a member of the GlaxoSmithKline group of companies. The registered address of GlaxoSmithKline Services Unlimited is 980 Great West Road, Brentford, Middlesex TW8 9GS.
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